A torch is a portable handheld electric light. A typical torch consists of a light source mounted in a reflector, a battery and a switch.
The source of light is an LED ie light emitting diode. In LED the longer leg is positive end and the shorter leg is negative end. It is a diode that allows current to flow only from positive end to negative end.
A dry cell converts stored chemical energy into electrical energy. Two or more cells form a battery.A dry cell is a zinc carbon cell.It produces voltage of about 1.5 volt. Zinc container act as negative electrode, carbon rod acts as positive electrode.The electrolyte used is a moist paste of ammonium chloride and zinc chloride. It is made up of metallic cylinder. It has a flat case and metal cap on top.The metal cap is positive end of cell and flat base is negative end of cell.
The switch is an electric device that is used to make or break the circuit.
Due to chemical reaction within the battery, the negative electrode build up an excess of electrons. When the cicuit is closed with a conductive path, the electrons are able to travel to the positive end.Thus in turn provides power to LED.Inside the LED the electrons recombine with the holes and energy is released in the form of light.
When the switch is in off position, the circuit is not complete and the current doesnot flow through it. Such circuit is called an open circuit.When switch is in On position the circuit is complete and current flows through it. Such circuit is called closed circuit.
